Abstract There is a fundamental gap in the understanding of how newly passed federal regulations have and will continue to affect the sales practices of Internet Tobacco Vendors (ITVs). In the past, they have enjoyed relatively few regulatory restrictions as compared to retail stores, resulting in widespread excise tax evasion and poor youth access prevention. 2009?s Family Smoking Prevention and Tobacco Control Act (FSPTCA), 2010?s Prevent All Cigarette Trafficking (PACT) Act, and 2016?s FDA Deeming Regulations have dramatically changed the environment for Internet tobacco sales by giving the FDA power to regulate tobacco, restricting the shipment of tobacco from ITVs, mandating age verification and tax reporting, and banning the sale of light tobacco and flavored cigarettes, and forthcoming regulations from FDA are anticipated to restrict ITV sales even further. The ITV industry has proven highly adaptable to attempts to regulate it, exploiting loopholes in regulations and increasing their offerings of less regulated products similar to those that have been banned. Continued in-depth surveillance of this industry is important to assess how implementation and enforcement of these regulations affects the industry, and to determine not only the extent to which ITVs comply with the regulations but also the ways they find ways to avoid compliance and/or adapt to regulations in new and unexpected ways. Our broad goal is to use state-of-the-art research methods to conduct extensive surveillance of the online retail environment for tobacco, to evaluate impact of regulations on this industry?s practices, and to disseminate our findings to policymakers in the interest of guiding future policy and enforcement efforts. Building on data and protocols developed over 17 years of studying ITVs, this goal will be achieved by pursuing six specific aims: 1. prepare comprehensive lists of online sellers of five categories of products: e- cigarettes, cigarettes, little cigars, hookah, and other tobacco products; 2. conduct ITV website content analyses to assess ITV sales practices and 3. conduct ITV youth purchase surveys to assess compliance with the FSPTCA, PACT Act, FDA Deeming, and other forthcoming regulations. The approach is innovative in that it achieves several firsts; content analyses and purchase surveys from hookah tobacco sellers, 4. evaluation of the effect of Deeming regulations on the ITV industry; and 5. Evaluation of the effectiveness of modern online age verification strategies not currently in broad use by ITVs, to determine whether they are effective and appropriate to recommend FDA require for online tobacco sales. The proposed research is significant because it will provide rapid detection of changes in ITV practices in response to new and forthcoming regulation as it 6. disseminates findings to FDA, regulators, and researchers to spur action, enabling the government to more effectively revise their regulatory and enforcement efforts, with a greater goal of reducing the public health threats posed by ITV sales.